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<PRE LANG="en-US"><FONT SIZE=5><B>Exponential integral</B></FONT>

<FONT SIZE=5><SPAN LANG="en-US"><B>ei</B></SPAN></FONT>

<FONT SIZE=4><SPAN LANG="en-US"><SPAN STYLE="font-style: normal">C</SPAN><SPAN STYLE="font-style: normal">alculates the exponential integral</SPAN><I>,</I></SPAN></FONT>
<FONT SIZE=4><SPAN LANG="en-US">for details see book of Hang T. Lau, “A Java Numerical Library for Scientists and engineers|”, Chapman &amp; Hall, 2004</SPAN></FONT>




<FONT SIZE=4><SPAN LANG="en-US"><B>Example: Can be run with F5 within the ScalaLab Editor (Ctrl-E to open the editor)</B></SPAN></FONT>


import java.text.DecimalFormat;
import numal.*;

public class Test_ei extends Object {
	
	public static void main(String args[]) {

    DecimalFormat fiveDigit = new DecimalFormat(&quot;0.00000E0&quot;);
    System.out.println(&quot;EI delivers:  &quot; +
          (fiveDigit.format(-Special_functions.ei(-0.5))));
	}
}</PRE>
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